1. Field of the Invention
This invention relates to short tube container filling devices having a check valve cooperating with the tube inlet to minimize flow disturbances and to prevent tube purging during the container filling operation.
2. Description of the Prior Art
Short tube filling devices are in common use in the filling of containers in soft drink bottling machines, as well as in breweries. In devices of this class, the short tube extends a short distance into the bottle or container during the process of admitting a beverage, such as a soft drink, beer or the like, to the container. The tube is provided for admitting a pressurized gas to the container in advance of the beverage so that the entry of the beverage can proceed by gravity influence and the charging gas can exit through the tube at high speed and with a minimum of frictional resistance.
The prior art includes such devices as disclosed in Meyer U.S. Pat. No. 3,067,785 of Dec. 11, 1962 and pertaining to a hollow stem having a ball check valve suspended adjacent the mouth of the stem by a rigid cage. A similar arrangement of tube and check valve device is shown in Breeback U.S. Pat. No. 2,770,263 of Nov. 13, 1956. Additional disclosures of ball check valves in short filling tubes can be seen in Naecker U.S. Pat. No. 3,090,408 of May 21, 1963, in Breeback U.S. Pat. No. 3,192,966 of July 6, 1965, and in Neumayer U.S. Pat. No. 1,022,968 of Apr. 9, 1912.
A problem with the foregoing types of ball check valves for a filling tube is the total pressure loss associated with the form of the inlet passage. The tube inlet has been found not to allow the gas to enter the tube in a smooth stream. This is undoubtedly due to the high friction losses created by the configuration of the inlet. The result of such losses is that the filling speed can be decreased compared to a simple open-ended tube. If a check valve is omitted, then the beverage will flow up into the tube, and on the next filling sequence that quantity of beverage will be forced into the next container with a considerable degree of violence. The end result is that certain beverage products can be caused to go "wild", resulting in a longer snift time and loss of product through foaming, as the container is removed from the sealing cup.
The ball check valves of the prior art do not achieve the smooth escape of the gas so that the filling cycle consumes more time. In view of this there is a residue of product in the tube which is blown into the next bottle which affects the next filling cycle by reason of the small droplets of product being blown into the next container to cause excessive foaming.